Method and apparatus for making filamentous mat



1959 J. E. COPENHEFER ETAL 3,459,613

METHOD AND APPARATUS FOR MAKING FILAMENTOUS MAT Filed July 29, 1965INVENTOR. John E. C'apenhe/er George J. //efi 3,459,613 METHOD ANDAPPARATUS FOR MAKING FILAMENTOUS MAT John E. Copenhefer and George J.Heb, Louisville, Ky.,

assignors to American Air Filter Company, Inc., LOUIS- ville, Ky., acorporation of Delaware Filed July 2, 1965, Ser. No. 475,650 Int. Cl.D04h 3/16 US. Cl. 156167 5 Claims ABSTRACT OF THE DISCLOSURE A methodand apparatus for the manufacture of fibrous mats including selectivevariation of the spacing between filaments wound on a rotating filamentcollector drum and apparatus to decrease the amount of materialdeposited at the ends of a fibrous mat formed on a rotating drum.

BACKGROUND OF THE INVENTION A well-known method and apparatus forformation of condensed mats of, for example, glass, comprisesreciproeating a filament feeding apparatus in a traverse axially along arotating drum. Molten glass issues through multiple orifices in thebottom of the feeder and the streams issuing therefrom are attenuatedinto glass fibers by winding upon the rapidly rotating drum. The furnaceis reciprocated back and forth across the length of the drum a pluralityof times to form a mat composed of a plurality of layers of spun fibers,the layers extending substantially from one to the other end of thedrum. When sufiicient traverses of the furnace have been effected tobuild the mat to the desired thickness, the collected mat is slitparallel to the axis of rotation of the drum and removed therefrom as asheet. The sheet can then be expanded by stretching the sametransversely to the line of slit.

A disadvantage frequently common to previous methods and apparatus formanufacturing such mats is that fewer fibers are deposited on the drumin the end reversal areas of the furnace traverse. This occurs becausethe furnace stops momentarily at each end of the traverse and all of theopenings in the orifice plate do not pass completely over the drum inthe end reversal areas to deposit the same number of filaments as aredeposited in the central portions of the drum. Increasing furnace dwelltime in the end reversal areas deposits more glass, but thecharacteristics of the material thus formed are different from thecharacteristics of the material in the central portion of the mat. Thematerial formed in the end reversal areas is generally of inferiorquality and considered scrap material to be discarded as waste.

In certain applications it is desirable to manufacture a condensed matof varying density throughout the thickness of the mat. This objectiveis currently accomplished, among other methods, through the use ofcollector wheels to collect mono-filaments of glass to form multi-strandfilaments for deposition on the rotating drum, or through the device ofslowing the speed of rotation of the rotating drum during the formationof the mat to form filaments of larger diameter.

In accordance with the present invention, a novel and useful method andapparatus for manufacturing filamentous glass mats is provided whereinthe waste normally associated with the portion of the mat formed in theend reversal areas of the traverse is materially reduced and a method isprovided to vary mat density in any desired manner throughout thethickness of the mat without the use of abrasive glass contactingdevices or collectors. Fur- States Patent 0 e we ther, the presentinvention provides a method of accomplishing both desirable objectivessimultaneously and cooperatively without sacrificing the effectivenessof either objective.

Various other features of the present invention will become obvious toone skilled in the art upon reading the disclosure set forthhereinafter.

More particularly, the present invention provides a method of making acondensed, filamentous mat of a plurality of layers of fibers wherein afilament feeding apparatus is transversely reciprocated axially along arotating drum, filaments are discharged from multiple openings in thefeeder and collected on the rotating drum. The filaments are collectedon the rotating drum to build a cylindrical mat composed of a successionof layers of fibers with each layer composed of a multiplicity ofhelical turns of fibers and extending generally from one end of therotating drum to the other.

In accordance with the present invention, during the formation of thefilamentous mat the filament feeder can be disposed at more than oneposition of angular displacement with relation to the rotating drum, theangle measured being determined by the position of the axis of rotationof the drum with respect to the position of the longitudinal axis of thefilament feeder. With such an arrangement, it is possible to collect thefibers into collected fiber filaments or strands as the longitudinalaxis of the furnace moves toward a substantially perpendicular positionrelative the rotational axis of the drum. This collection of filamentswith more than one position of angular displacement yields a mat productof graded density.

Further, in accordance with the present invention, the traversing speedof the feeder drive means can be varied throughout the formation of thefilamentous mat, and in particular, can be increased during the timewhen the filament feeder is in the end reversal areas of the drum tomaterially reduce the residence time of the feeder in the end reversalareas and thus materially reduce the amount of glass deposited in theend reversal areas of the traverse.

The present invention further provides for formation of filamentous matsof variable density in still a further manner wherein the traversingspeed of the reciprocating furnace can be changed relative the speed ofthe drum in a preselected manner during the formation of a unit mat,regardless of the location of the feeder in its traverse and regardlessof the aforementioned angular displacement. In accordance with thepresent invention, the preselected speed change results in a depositionof fibers onto the drum at preselected differing angles of lay with suchdiffering angles of lay causing certain fibers to group together uponexpansion of the mat so as to produce varied density in the completedmat.

Referring to the drawing which discloses one advantageous embodiment ofthe present invention.

FIGURE 1 is an elevational view of an apparatus used to manufacturefilamentous mats taken from the end of the rotating drum, showing thelongitudinal axis of the filament feeder in angular relation withrespect to the longitudinal axis of the rotating drum;

FIGURE 2 is an elevational view taken from the front of the rotatingdrum;

FIGURE 3 is a horizontal view showing orientation of the gear adjustingmechanism for the feeder assembly; and

FIGURE 4 is an enlarged, partial view of a sprocket taken in a planepassing through line 44 of FIGURE 1.

Referring to the drawings, there is shown a generally horizontal drum 1which is normally rotated at high speed (by means not shown) whereonfilaments 4 are collected to form a condensed mat. Furnace 2, containingsuitable molten material, for example glass, has in the bottom sidethereof a plate (not shown) including a multiplicity of orifices throughwhich said molten material issues to form filaments 4. The orifices insaid plate can be arranged in any desired geometrical configuration butusually there are longitudinally-extending rows of orifices in theplate, and in the normal apparatus, each row can contain 50 orificeswith the rows spaced approximately one inch apart. The diameter offilaments 4 drawn from the furnace 2 to the rotating drum 1 isinfluenced by the rotational speed of drum 1. Filaments are drawn to thedrum as individual monofilaments, or as strands composed of a number ofmonofilaments, depending upon the proximity of adjacent filaments asdrawn from the filament feeder, Furnace 2 is supported from furnacecarriage 10 by yoke 3 mounted on shaft 6 affixed to rtatable supportplate 8. Support plate 8 is rotatably mounted within and to carriage 10to turn furnace 2 to any desired angular relation with respect to therotational axis of rotating drum 2.

Gear teeth are provided around the periphery of support plate plate 8.These teeth cooperate with worm gear 7 aifixed to shaft 20 mounted inworm gear shaft bracket 21. Handle 9, affixed to shaft 20, serves topermit manual turning of shaft 20 and worm gear 7 to orient thelongitudinal axis of the furnace relative to the longitudinal axis ofthe rotating drum 1 in any desired angular relation. Furnace carriage ismounted on wheels 11 disposed in cooperative spaced relation to move ontracks 12. Tracks 12 are disposed in straddling relation above adownturning edge of the rotating drum 1 and extend generally parallelthe longitudinal axis of the drum to carry the furnace carriage 10 inreciprocatory traverses along said downtuming edge. Variable speedfurnace drive means 17 is provided to move furnace carriage 10 andfurnace 2 along tracks 12. Drive means 17 includes motor 18 and variablespeed gear box 19 which is connected to turn sprocket 16 to driveendless chain mounted around it and idler sprocket 22 at a preselectedspeed. The speed of the furnace drive means transmitted to sprocket 16can be controlled by a variable rheostat (not shown) in the power lineto the motor 18, or by integral speed changing mechanism (not shown) inthe variable speed gear box 19. Any desired means such as a time clock(not shown) may be used to control the rheostat or the variable speedgear box to change the speed of the furnace drive means 17. Drive pin 14is afiixed to chain 15 and nests in a vertically-extending pinreceivingslot 13 on arm 13 which is mounted to furnace carriage 10. Pin 14 isfree to move in a vertical direction in slot 8 while driving the furnacecarriage 10 in a generally horizontal direction on tracks 12 in responseto the movement of chain 15, For example, the pin moves along with chain15 in a horizontal direction between sprocket 16 and 22 and drives thefurnace correspondingly. The pin then moves around the sprockets andduring the period when pin 14 is moving around a sprocket and in agenerally vertical direction in the slot, there is a correspondinglydecreased horizontal motion of the furnace 2. Further movement of pin 14reverses the direction of horizontal travel of furnace 2, and pin 14once again resumes a generally horizontal movement corresponding totravel between sprockets. The portion of the traverse during the periodwhen drive pin 14 is passing around a sprocket is best described as theend reversal area of the furnace traverse. The portion of the mat formedduring the period when the furnace is in the end reversal areas of thetraverse is usually of less desirable quality than the part of the matformed when the furnace is in the central portion of the rotating drumbecause all of the orifices of the furnace do not pass over the endreversal areas to deposit filaments, so there is less glass deposited inthe end reversal areas than in the central portion of the mat, and theedge portions are further undesirable because of undesirable angles oflay of the fibers due to furnace speed changes. It will be realized bythose skilled in the art that any other suitable means may be used as afurnace drive means 17 hereinbefore illustrated without affecting thescope or intent of the present invention.

In operation, the drum 1 is rotated at a desired speed and chain 15moves pin 14 at a speed determined by the preselected speed of thevariable speed drive means 17, the furnace 2 being driven accordingly.The width of the mat formed on rotating drum 1 is determined by thelength of the furnace traverse.

In one advantageous example, the speed of furnace drive means 17 ischanged relative the drum speed periodically regardless of the positionof the feeder in the traverse, and a mat is formed of fibers, a portionof which have one angle of lay and at least another portion of which hasanother angle of lay. It is to be understood that this can be done in anumber of ways as described hereinafter and it further is to beunderstood that the preselected periodic change can occur at anylocation of the filament feeder in its traverse. For example, thefurnace can be run for a preselected period of time (one houras anillustration) at a constant speed relative the drum speed. Then foranother preselected period of time (onehalf hour, for example) thefurnace can be run on a cycle, combining two preselected but differentspeeds relative to the drum speed which deposits fibers on the drum attwo different angles of lay. One of these two preselected speeds can beapproximately equal to the original speed and the other can be less.During subsequent preselected periods of time (one-half hour each, forexample) the percentage of time of the lesser of the two pre-selectedspeeds can be increased. It is to be understood that the presentinvention is not to be considered as limited to the specific cyclingarrangement aforedescribed and that the lower speeds can be taken tozero or standstill without detriment to the concept of the presentinvention. It further is to be understood that, as is known in the art,suitable binder materials can be applied to the mat during or after itsformation. If the mat thus formed is subsequently cut parallel to thelongitudinal axis of the drum and expanded by drawing or stretching itfrom one of its edges, which extends in the general direction of thefibers, an expanded mat results wherein those fibers deposited at agreater angle of lay, corresponding to a higher relative speed betweenfeeder and drum, are substantially straightened, and those fibersdeposited at a lesser angle of lay loop or curl and are grouped toprovide graded mat density as a function of such grouping. The densityof a mat thus formed changes incrementally throughout the thickness ofthe mat.

As aforestated, the portion of the mat formed in the end reversal areasof the traverse has been generally considered waste and thereforediscarded. By the advantageous method herein disclosed, the amount ofwaste formed in the end reversal areas is reduced by decreasing the timethe furnace is in the end reversal areas, thereby reducing the amount ofglass deposited and to be wasted in the end reversal areas. The speed offurnace drive means 17 is increased when pin 14 approaches sprocket 16or 22 and the furnace 2 is entering the end reversal areas of thetraverse as can be seen in FIGURE 4. The speed increase of the drivemeans can be accomplished through use of limit switches 23 and 24.Switch 23 initiates an increase in speed of furnace drive means 17 whenpin 14 engages the lever of the switch 23 to actuate a control mechanismsuch as, for example, a cooperating rheostat (not shown in detail) in asuitable power supply circuit 25 to motor 18. As pin 14 leaves thesprocket, it contacts the lever of switch 24 which causes said furnacedrive means to resume normal speed by actuating the rheostat in thepower circuit 25 in a reverse direction. The decreased residence time ofthe furnace in the end reversal portions of the traverse results in thedeposition of fewer fibers in these areas of the drum than wouldnormally occur without increasing the speed of the furnace traverse, andsince the portions of the mat formed in the end reversal areas arediscarded as waste, the total amount of glass discarded as waste isdecreased. It will be understood that a similar action obtains at theother end of chain 15 due to another set of switches 23 and 24'.

As shown in the drawing, furnace 2 is pivotally mounted on the furnacecarriage by means of rotatable plate 8 and shaft 6, and the longitudinalaxis of the furnace can be turned in angular relation to thelongitudinal axis of the drum by turning worm gear 7. Handle 9, attachedto worm gear 7 by shaft 20, can be turned as desired to manually adjustthe angular position of the furnace. It will be realized by one skilledin the art that gear 7 can be continuously turned during the formationof the condensed mat either manually or by any suitable means tocontinuously change the angular relation between the longitudinal axisof furnace 2 and drum 1.

The width of the waste portion of the mat formed in the end reversalareas is approximately equal to the width of the band of filaments 4wound on the drum. Thus, if the longitudinal axis of the furnace orificeplate is parallel the longitudinal axis of the drum, the width of thewaste portion formed is approximately equal to the width of the furnace2 plus the radius of the sprocket 16 or 22. As is known in the art, theamount of waste formed in the end reversal areas of the mat is reducedby decreasing the width of the band of filaments 4 wound on drum 1. Inmost furnaces reduced waste will result when the longitudinal axis ofthe furnace is at an angle other than parallel to the longitudinal axisof the drum. In addition to the waste reduction at the end areas of thedrum as a result of effecting a preselected angular relation other thanparallel between the longitudinal axis of furnace 2 and drum 1 at suchend areas, the present invention recognizes that angular variationintermediate the end reversal areas provides for variable fiber groupingwith resulting formation of a condensed mat of variable densitythroughout the thickness of the mat when the mat is expanded. A portionof such mat can be formed with the longitudinal axis of thereciprocating furnace 2 at substantially less than a right angle withrespect to the longitudinal axis of the rotating drum. Another portionof the mat can be formed with the longitudinal axis of furnace 2 at anincreased angular relation approaching a right angle to thelongitiudinal axis of rotating drum 1. The portion of the mat formedwith the longitudinal axis of furnace 2 at substantially less than aright angle in relation to the longitudinal axis of rotating drum 1 iscomposed primarily of individual filaments in comparatively spacedrelation formed with only a few fibers composed of a plurality ofmonofilaments which result when several monofilaments adhere to eachother after being attenuated from furnace 2 in contiguous relation. Theportion of the rnat formed with the longitudinal axis of furnace 2 at anincreased angle relation to the longitudinal axis of drum 1 is composedprimarily of strands of monofilaments formed when the filaments areattenuated in contiguous relation and adhere to each other when wound ondrum 1. If the mat thus formed is expanded after it has been cut alongthe longitudinal axis of the drum and removed therefrom by drawing itfrom one of its edges transverse the line of cut, the density of theresulting expanded mat is high in the portion formed when the furnacewas disposed at substantially less than a right angle because of thegreat number of individual monofilaments in this portion of the mat. Thedensity of the mat is lower in the portion formed when the longitudinalaxis of the furnace was disposed at increased angular relation to thelongitudinal axis of the drum because fibers are grouped into strands.It will be realized by one skilled in the art that a corresponding matwith similar characteristics could be formed by reversing the sequenceof steps above outlined. Likewise, the formation of a condensedfilamentous mat having continuously varying fiber density through thethickness of the mat can be accomplished by starting the formation ofthe mat with the longitudinal axis of furnace 2 at a preselected anglewith respect to the longitudinal axis of drum. 1 and continuallyincreasing the angular relation between the longitudinal axis of furnace2 with respect to the longitudinal axis of drum 1 at a predeterminedrate of movement. The initially formed portion of said mat will becomposed primarily of monofilaents, but as the angular displacementincreases, the monofilaments will fall one on the other in increasingnumbers and therefore increase the total number of fibers which aregrouped.

It is to be understood that for the purposes of this invention thelongitudinal axis of the furnace can be correlated to the longitudinalaxis as determined by a row of holes in the orifice plate. It further isto be understood that the aforedescribed inventive features of varyingthe traversing speed of the feeder means, of varying the angulardisplacement of the furnace relative the drum and of inrceasing thetraversing speed in the reversal areas can be selectively combined inthe manufacturing process of filamentous mat in accordance with theresults desired for the final product.

The invention claimed is:

1. A method of making a condensed fibrous mat of a plurality of layersof fibers comprising: transversely reciprocating filament feeder meansat a selected traversing speed in spaced relation from and axially alonga drum; rotating said drum a multiplicity of times during each traverseof said feeder means; feeding a plurality of filaments from amultiplicity of spaced orifices in the bottom of said feeder means tosaid drum during successive traverses so filaments wound on said drum inone revolution of said drum overlap a portion of said filaments wound onsaid drum during the previous revolution of such feeder means to buildup a corresponding succession of layers of filaments with each layercontaining a multiplicity of helical turns extending continuouslythrough the central area from one end reversal area to the other;pivoting said filament feeder means about an axis extending through theplane of said bottom wall to more than one position during the formationof said fibrous mats to vary the distance between adjacent filamentswound on said rotating drum.

2. A method for making a fibrous mat of a plurality of layers offilaments comprising: transversely reciprocating filament feeder meansat a selected traversing speed in spaced relation from and axially alonga drum; rotating said drum a multiplicity of times during each traverseof said feeder means; feeding a plurality of filaments from amultiplicity of spaced orifices in a bottom of said feeder means to saiddrum during successive traverses of said feeder means so filaments woundon said drum in one revolution of said drum overlap a portion of saidfilaments wound on said drum during the previous revolution to build upa corresponding succession of layers with each layer containing amultiplicity of helical turns extending continuously through the centralarea from one end reversal area to the other; forming a portion of saidmat wherein said feeder means is in one angular position relative to anaxis extending through the plane of said feeder bottom wall and forminga second portion of filamentous mat wherein said feeder means is at asecond angular position relative to said axis extending through saidbottom wall to vary the distance between adjacent filaments wound onsaid rotating drum wherein the difference between said first angularposition and said second angular position is between 0 and 3. Method formaking a fibrous mat of a plurality of layers comprising: transverselyreciprocating filament feeder means at a selected traversing speedaxially along a rotating drum, feeding a plurality of filaments from amultiplicity of spaced orifices in a bottom wall of said feeder means tosaid drum during the successive traverses of said feeder to build up acorresponding succession of :layers of filaments so filaments wound onsaid drum during one revolution overlap a portion of the filaments woundon said drum during a previous revolution to form filament layerscontaining a multiplicity of overlapping helical turns extendingcontinuously through the central areas of said drum from one endreversal area to the other; and, continuously pivoting said filamentfeeder means about an axis extending through the plane of said bottomwall to continuously vary the spacing between adjacent filamentsdeposited on said rotating drum.

4. Apparatus for forming a filamentous mat comprising: a rotating drum;filament feeder means having filament feeding orifices in a bottom wallthereof and movably mounted for successive reciprocatory traverses alongtracks disposed above a downturning edge of said drum to feed filamentsfrom said filament feeder means to said rotating drum; filament feederdrive means for driving said filament feeder means in said traversealong said path; means for varying the speed of said feeder drive meansto correspondingly vary the traversing speed of said filament feedermeans; feeder pivot means to selectively pivot said feeder means aboutan axis extending through said bottom Wall.

5. Apparatus for forming a filamentous mat comprising: a rotatable drum;track means disposed along an edge of said rotating drum; carriage meansmounted for movement along said tracks; filament feeder means havingorifices in a bottom wall thereof to feed filaments from said carriagemeans to said rotating drum, said feeder means being mounted on saidcarriage means for reciprocatory motion through successive traversesalong said downturning edge of said drum to feed filaments to saidrotating drum; filament feeder drive means including endless belt meansmounted for travel around spaced wheel means selectively disposed alongthe Width of said downturning edge of said rotating drum means drivinglyconnected to said filament feeder means to drive said feeder means backand forth along said downturning edge in response to movement of saidendless belt means in one rotational direction; and, means forincreasing the speed of said feeder drive means during the portion ofthe reciprocatory traverse of said feeder when said filament feedermeans is in the end reversal area of a traverse and for decreasing thetraversing speed of said feeder drive means when said filament feedermeans leaves said end reversal area.

References Cited UNITED STATES PATENTS 2,798,531 7/1957 Jackson 156174XR 2,913,037 11/1959 Modigliani 156-425 XR 3,029,649 4/ 1962 Steyh 74373,051,602 8/1962 Schairbaum 156-167 XR EARL M. BERGERT, Primary ExaminerM. E. MCCAMISH, Assistant Examiner US. 01. X.R. 156-169, 425

